Notice - undefined variable checksums

Description

Saw a PHP Notice referencing an undefined variable checksums during the manual update to 3.7. The page redirected to the About page before I caught the file and reference number, but Nacin says that "Line 753 wp-admin/includes/update-core.php needs an isset() check", so my guess is that line 753 wp-admin/includes/update-core.php needs an isset() check...